GY-273 HMC5883L Triple Axis Magnetometer Compass Sensor Module for Arduino & Raspberry Pi

Specifications:

• Sensor IC: HMC5883L (Honeywell)
  
• Communication: I2C Digital Interface
  
• Input Voltage: 3.0V – 5.0V (Onboard Regulator)
  
• Measuring Range: ± 1.3 to 8 Gauss
  
• Heading Accuracy: 1° to 2°
  
• Resolution: 5 milli-gauss
  
• Dimensions: 18mm x 14mm
  
• Pinout: VCC, GND, SCL, SDA, DRDY

Key Applications:

• Autonomous Navigation: Giving a "Heading" to Arduino-based rovers.
  
• Drone Stability: Magnetic North compensation for GPS-enabled flight controllers.
  
• Handheld Compasses: Digital orientation displays for hikers and hobbyists.
  
• Interference Detection: Detecting nearby magnetic fields in industrial environments.

Project Evolution

• Past Projects (Prerequisites): If you have successfully interfaced a basic MPU6050 (Accelerometer/Gyro), you’ve likely noticed "Yaw Drift"—where the robot thinks it's turning when it's not.
  
• Feature Upgrade: Adding the HMC5883L unlocks Absolute Heading. Unlike a gyro which only measures relative change, this magnetometer provides a fixed reference point (Magnetic North), eliminating long-term drift.
  
• Effort/Requirements: Intermediate. Requires basic understanding of I2C and "Hard-Iron" calibration (rotating the sensor in a circle to offset local magnetic interference).

Virtual Technician & Wiring

• ⚠️ Safety Warning: Avoid mounting this module near high-current DC motors or large magnets, as the magnetic field from the wires will distort the readings.

Pin Mapping (Arduino Uno):

• VCC -> 5V
• GND -> GND
• SCL -> A5 (or dedicated SCL pin)
• SDA -> A4 (or dedicated SDA pin)
• DRDY -> Leave disconnected for basic use (Data Ready interrupt).

Package Includes:

1 x GY-273 HMC5883L Triple Axis Magnetometer Compass Sensor Module for Arduino & Raspberry Pi

Frequently Asked Questions (FAQ)

1. Does the GY-273 work with 5V Arduino boards?
   Yes, the onboard regulator makes it compatible with 3.3V and 5V systems.
2. What is the difference between HMC5883L and QMC5883L?
   They use different I2C addresses and registers. This listing is for the HMC variant (Address 0x1E).
3. Why are my heading readings jumping around?
   Check for nearby metal or motors. Use a "Tilt-Compensation" algorithm if the sensor isn't perfectly flat.
4. Do I need to calibrate this sensor?
   Yes, "Hard-Iron" calibration is required for accurate North-finding in your specific environment.
5. What is the I2C address of the HMC5883L?
   The default 7-bit address is 0x1E.
6. Can I use this with Raspberry Pi?
   Yes, via the I2C pins (GPIO 2 and 3).
7. Is the pin header soldered?
   The module typically ships with an unsoldered 5-pin male header for flexibility.
8. How do I convert Gauss to Heading?
   Use the atan2(y, x) function in your code to calculate the angle in radians.
9. What is the DRDY pin for?
   It signals the microcontroller that a new measurement is ready to be read.
10. Can this detect a magnet from a distance?
    Yes, it can detect magnetic disturbances, though it is designed as a compass.
11. Is this sensor tilt-compensated?
    No, this is a 3-axis magnetometer only. For tilt compensation, pair it with an accelerometer.
12. What is the current consumption?
    Extremely low, typically around 100uA during measurement.
13. Can I use multiple HMC5883L on one I2C bus?
    The address is fixed, so you would need an I2C multiplexer like the TCA9548A.
14. What library should I use for ESP32?
    The standard Arduino HMC5883L libraries work perfectly with ESP32.
15. Does magnetic declination matter?
    Yes, for true geographic North, you must add your local declination angle to the magnetic reading.
16. How fast can it sample?
    It supports data output rates up to 75Hz.
17. Is it waterproof?
    No, this is an open circuit board. Use an enclosure for outdoor use.
18. Can it work near a battery?
    Small batteries are fine, but keep away from high-current LiPo discharge wires.
19. What happens if I reverse VCC and GND?
    Reverse polarity will likely damage the IC; always double-check connections.
20. Why is my code saying "Sensor Not Found"?
    Check wiring and ensure your library is targeting the correct I2C address (0x1E).